Fish oil supplementation for major depression continues to garner positive reviews from scientists and clinicians. A recent review of the past few years of data shows significant positive effects without negative side effects for a variety of patients with differing diagnoses. Some recent findings:
Systemic inflammation is increasingly recognized as an associated factor in many mental illnesses. MoodSurfing has investigated the importance of dealing with inflammation as part of a comprehensive approach to depression and physical health. Omega 3 fatty acids, usually taken as a fish oil supplement, have been found helpful, particularly when the symptoms of depression are physical (change in appetite, loss of energy, sleep problems).
Omega 3 fatty acids, especially eicosapentaenoic acid (EPA) have been shown to have helpful effects in mood disorders, but not in depression associated with pregnancy or comorbid with other conditions, such as cardiovascular disease. The other primary Omega 3 fatty acid found in fish oil, docosahexaenoic acid (DHA) does not seem to have any effect. So it is important to read labels carefully and find a fish oil supplement that is high in EPA.
Fish oil has been shown helpful as an adjunctive treatment, when the patient is also taking medication for depression, as well as on its own. There is also some evidence that it can be helpful for people who appear to have depressive symptoms, but have not received a formal diagnosis. However, there is no evidence of effect of fish oil supplementation in preventing depression. There is some evidence that the effects are stronger when fish oil supplementation is taken for more than a minimum of 12 weeks at a dose of 1500 – 3500 mg per day. Again, it is important to note that the supplement taken must contain more EPA, not DHA. We recommend the website Consumer Labs for analysis and review of supplements to be sure they contain the ingredients on the label.
There are only a few small studies looking at the use of fish oil supplementation in bipolar disorder, but what evidence there is shows some effect on depressive symptoms, but no effect was found on mania. Most studies found no adverse effects or mania/hypomania associated with use of fish oil.
In all cases, it is important to keep in mind that the importance of a healthy diet cannot be ignored. People with mental health challenges often eat a poor diet with a lot of empty calories. A healthy diet including vegetables, fruits, nuts and seeds, and two to three helpings of fish per week is the basis of any health care and may actually do more to improve health than taking supplements.
Reference:
Firth J, Teasdale SB, Allott K, Siskind D, Marx W, Cotter J, Veronese N, Schuch F, Smith L, Solmi M, Carvalho AF, Vancampfort D, Berk M, Stubbs B, Sarris J. The efficacy and safety of nutrient supplements in the treatment of mental disorders: a meta-review of meta-analyses of randomized controlled trials. World Psychiatry. 2019 Oct;18(3):308-324. doi: 10.1002/wps.20672. PMID: 31496103; PMCID: PMC6732706.